Method of molding flexible rubbers



Jan.19,1937. HMALM 2,068,239.

METHOD OF MOLDING FLEXIBLE RUBBERS Filed April 2o, i936 INVENTOR /f/VRY MAL/vf ATi-ORNEY Patented Jan. i9, ibid? rare is @riginal application December 2l, 1935, Serial No. 55,539. Divided and this application April 20, i936, Serial No. '75,337

I Claim. (Cl. 18-55) This invention relates to rubbers employing sole and heel portions and an upper body part for partially enveloping or covering a shoe upper; and the object of the invention is to provide an article of apparel oi the class described composed entirely of rubber whereby all portions of the article are capable of expansion and contraction, and further, whereby the article may be folded or rolled into a relatively small compact package facilitating the placement of a pair of rubbers in a pocket of a garment, pocketbook or the like to carry the same when not in use upon the shoes of a wearer; a further object being to provide an improved method of molding rubbers of the class under consideration to insure the proper iitting of the rubber upon the shoe and to otherwise produce a neat and iinished appearance; and with these and other objects in view, the invention consists in an article of manufacture of the class described, which is produced in accordance with the method more fully hereinafter described and claimed.

The invention described and claimed herein is a division oi my application Serial Number 55,539, nled by me December 2l, 1935, and is fully disclosed in the following speciiication of which the accompanying drawing forms a part, in which the separate parts of my improvement are designated by suitable reference characters in each of the views, and in which:

Fig. l is a side view ci two die or mold parts illustrating the general contour of the parting line of said parts.

Fig. 2 is a longitudinal sectional View through H the die or mold parts shown in Fig. l and diagrammatically illustrating` the method oi using the same.

Fig. 3 is a side View of a rubber formed from the dies or molds shown in Figs. l and 2; and,

Fig. 4 is a sectional view of a container showing a pair of rubbers compactly folded therein.

In Figs. l and 2 of the drawing, I have diagrammatically illustrated the separate parts of a mold or die employed for forming my improved r rubbers. In said figures, 5 represents the lower die or mold part; 6 the upper part; and i the core. Suitable dowel or alining pins li will be provided for bringing the cavity i) of the part 5 and the cavity ill of the part i5 in proper registering alinement and with the boundary edges of the cavity 9 in direct registering alinement with the corresponding edges of the cavity lil. The core 'l has similar dowel or alinement pins il for properly positioning and alining the core within the cavities 9 and l0.

The pins il will preferably be attached to the core l and enter apertures i2 in the part 5, which apertures open through the lower surface I3 of the part 5 to facilitate the insertion of other pins or tools to act as means for ejecting the core from the part 5 after a rubber has been formed thereon. f

In the operation of forming or molding a rubber, sheets, strips or particles of rubber are first placed upon the side walls 5a oi the cavity 9, after which the core l will be mounted inposition, and then a preformed sheet or strip of rubber will be laid upon the core l, or a number of such strips or sheets, to substantially build up or form about the core of the required amount of rubber to be molded into the sole and heel portions of the resulting article, after which the die or mold part ii is placed in position.

At this time, it will be understood that the surfaces ma, lb of the cavityr is forming the lower surfaces of the sole and heel portion of the resulting article may be engraved or otherwise formed to produce the desired rough contour or tread on the sole and heel portions of the resulting article. The intermediate surface itc may also have thereon such markings as to apply a trade mark, name or other advertising or descriptive literature includingI a designation oi size which will appear on the resulting article.

It will be understood that the die parts 5 and 6 will be heated in any desired manner, and will be held together under pressure during the vulcanization oi the rubber disposed within the cavities 9 and l around the core l. Under this treatment, the rubber or rubber compound employed will form a homogeneous article upon the core l, and when sufficient time has been allowed to effect complete vulcanization, the upper part of the mold is raised, the core l is then removed from the part 5 and the resulting rubber is removed from the core l, after which the article thus formed is trimmed to remove any flare or excess rubber that may prevail along the parting line dened by the two die or mold parts and around the opening formed in the top of the resulting article, At this time, he article may also be finished by the application of a nishing coating, such for example as a coating of lacquer.

In considering Figs. l and 2 of the drawing, it will appear that the core as well as the mold cavities or impressions s and lll are so arranged as to mold the finished article or rubber in a curved contour, that is to say, the back of the heel oi the rubber as well as the toe portion of the sole are raised with respect to the central portion of the rubber, the purpose of which is to shorten -the upper edges I4 of the side walls I5 of the resulting rubber I6, a side View of which appears in Fig. 3 of the drawing so that when the rubber is mounted upon the shoe of the wearer, the side edges I4 centrally of the rubber and the side walls I5 thereof will t snugly upon both side surfaces of the shoe. By reason of this manner of molding the rubber, the toe portion I'I and heel portion I3 will fit snugly upon the toe and heel portions of the shoe, especially with respect to the upper and lower surfaces thereof. The sole I9 of the rubber will be considerably thicker than the rubber upper, especially bearing in mind the roughened tread portion I9a thereof, and the heel 20 is preferably made heavier than the sole I9 and also includes a roughened tread 25a.. The sole and heel join the upper or side walls I5 in rounded edges Ib and 20o which project slightly beyond the surface of the wall I 5.

In Fig. 3 of the drawing, I have indicated at 2l a dot and dash line extending longitudinally of the side edges of the sole and heel I9, 20 and through the arch of the rubber; and this line represents the parting line 2Ia between the die or mold parts 5 and 6 as is indicated in Fig. 1 of the drawing. This method of forming rubbers will not only simplify the manufacture thereof but will also enhance the appearance of the resulting article by maintaining the trimming line, above referred to as the parting line 2I, substantially upon the outermost protruding point of the rounded projecting edges of the sole and heel of the rubber. This eliminates the defacing of the upper or side Walls I5 of the rubber, as would otherwise be experienced and also facilitates removal of the mold parts 5 and 6 from the molded rubber. I

By forming articles of apparel of the class described in the manner herein set forth, by'reason of the fact that the product is composed entirely of rubber, the same can be produced in relatively few sizes, such for example as, large, medium and small for mens sizes and the same for women, and large, medium and small for the childrens sizes. In addition to the extensibility of the upper structure of the rubber, the sole and heel of the rubber is also capable of extension to fit different sizes as well as different contours of a shoe.

Rubbers produced in the manner described will be comparatively light in Weight and may be compactly rolled or folded together as indicated at Ilia, I Sb, Fig. 4 of the drawing, and placed in a suitable container, pouch or wrapper 23 in said figure. 'Ihis container 23 is preferably composed of rubber or of waterproof material so that a pair of wet rubbers may be placed in the container 23 and then placed in a pocket of a garment, pocket book or handbag for storage when not in use.

From the foregoing, it will appear that my improved article of manufacture will encourage the removal of rubbers from the feet of the wearer on the many occasions where rubbers have otherwise been worn indoors where the protection is not required, causing discomfort to the wearer. This encouragement is primarily due to the fact that a pair of rubbers may be folded or rolled into a very compact and non-bulky package.

My invention is not limited to the particular form and contour of the rubber herein shown and described which is primarily a childrens or mans rubber, as the same may be applied to rubbers for women, and furthermore, the styles and contour of the respective rubbers may be changed to suit the fancy or desires of a manufacturer.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

The herein described method of forming an article of footwear composed entirely of rubber, which consists in forming the entire article by a single molding operation, said molding operation consisting of shaping sheets or particles of unvulcanized rubber in a mold to form continuous sole and heel portions, an upper shoe engaging portion, side walls sufficiently short in length to normally support the sole and heel portions in raised and angular position to each other, curved peripheral edges on the sole and heel portions and a iin disposed along said curved edges, then vulcanizing said formed article while in said mold by applying heat thereto, then removing the article from the mold, and` then trimming said curved edges to remove the iin and otherwise finishing the rubber to form the finished article, the trimming being substantially invisible on said edges of the sole and heel portions.

HENRY MALM. 

